Sensor chip and electronic device

Abstract

A sensor chip and an electronic device with SPAD pixels each including an avalanche photodiode element. The sensor chip includes a pixel area having an array of pixels, an avalanche photodiode element that amplifies a carrier by a high electric field area provided for the each of the pixels, an inter-pixel separation section that insulates and separates each of the pixels from adjacent pixels, and a wiring in a wiring layer laminated on a surface opposite to a light receiving surface of the semiconductor substrate that covers at least the high electric field area. The pixel array includes a dummy pixel area located near a peripheral edge of the pixel area. A cathode and an anode electric potential of the avalanche photodiode element arranged in the dummy pixel area are the same, or at least one of the cathode and anode electric potential is in a floating state.

What is claimed is: 
     
       1. A sensor chip, comprising:
 a pixel array section including a pixel area in which a plurality of pixels is arranged in rows and columns; 
 an avalanche photodiode element that amplifies a carrier by a high electric field area provided for the each of the pixels; 
 an inter-pixel separation section that insulates and separates the each of the pixels from another pixel adjacent to the each of the pixels in a semiconductor substrate in which the avalanche photodiode element is formed; and 
 a wiring that is arranged in a wiring layer laminated on a surface being opposite to a light receiving surface of the semiconductor substrate in such a way as to cover at least the high electric field area, 
 wherein the pixel array section includes a dummy pixel area located near a peripheral edge of the pixel area, and 
 a cathode electric potential and an anode electric potential of the avalanche photodiode element that is arranged in the dummy pixel area are a same electric potential, or at least one of the cathode electric potential and the anode electric potential is in a floating state. 
 
     
     
       2. The sensor chip according to  claim 1 , wherein a cathode and an anode of the avalanche photodiode element arranged in the dummy pixel area are short-circuited. 
     
     
       3. The sensor chip according to  claim 1 , further comprising:
 a sensor substrate in which the avalanche photodiode element is formed; 
 a logic circuit substrate in which a quenching resistance and an inverter are formed; and 
 a wiring layer that includes a sensor-side wiring layer arranged opposite the sensor substrate and a logic-side wiring layer arranged opposite the logic circuit substrate and that electrically couples the sensor substrate and the logic circuit substrate to each other, 
 wherein the cathode and the anode of the avalanche photodiode element arranged in the dummy pixel area are short-circuited in the logic-side wiring layer. 
 
     
     
       4. The sensor chip according to  claim 1 ,
 wherein the pixel array section includes a reference pixel area located at a center of the pixel area, 
 anodes of a plurality of the avalanche photodiode elements arranged in the reference pixel area are coupled to one another by a common wiring, 
 anodes of a plurality of the avalanche photodiode elements arranged in the dummy pixel area are coupled to one another by a common wiring, and 
 the anodes of a plurality of the avalanche photodiode elements arranged in the reference pixel area and the anodes of a plurality of avalanche photodiode elements arranged in the dummy pixel area are separated from each other. 
 
     
     
       5. The sensor chip according to  claim 1 ,
 wherein each of pixels arranged in the reference pixel area includes
 the avalanche photodiode element, 
 a quenching resistance coupled to the avalanche photodiode element in series, and 
 an inverter that outputs a received light signal on a basis of electrons having been multiplied in the avalanche photodiode element, and 
 
 each of pixels arranged in the reference pixel area includes the avalanche photodiode element and does not include the quenching resistance that is coupled to the avalanche photodiode element in series, and the inverter that outputs the received light signal on a basis of the electrons having been multiplied in the avalanche photodiode element. 
 
     
     
       6. An electronic device, comprising:
 a sensor chip including
 a pixel array section including a pixel area in which a plurality of pixels is arranged in rows and columns, 
 an avalanche photodiode element that amplifies a carrier by a high electric field area provided for the each of the pixels, 
 an inter-pixel separation section that insulates and separates the each of the pixels from another pixel adjacent to the each of the pixels in a semiconductor substrate in which the avalanche photodiode element is formed, and 
 a wiring that is arranged in a wiring layer laminated on a surface being opposite to a light receiving surface of the semiconductor substrate in such a way as to cover at least the high electric field area, 
 wherein the pixel array section includes a dummy pixel area located near a peripheral edge of the pixel area, and 
 a cathode electric potential and an anode electric potential of the avalanche photodiode element that is arranged in the dummy pixel area are a same electric potential, or at least one of the cathode electric potential and the anode electric potential is in a floating state.